NEW YORK (Reuters) – An upstart website has been blocked by a federal judge from streaming broadcast network shows and live broadcasts of Major League Baseball games in violation of federal copyright law.

The ruling by U.S. District Judge Naomi Reice Buchwald against ivi Inc came 20 days after U.S. prosecutors seized 10 popular websites that they said illegally streamed live sports and pay-per-view events over the Internet.

Tuesday's preliminary injunction blocks Seattle-based ivi from providing feeds to clients who download its TV player and pay a $4.99 monthly fee.

In response to the ruling, ivi told subscribers it will shut down most of its broadcast channel offerings.

Chief Executive Todd Weaver in an emailed statement said the company will appeal the Manhattan judge's ruling.

Ivi had filed a pre-emptive lawsuit against the broadcasters last September 20, one week after the company's launch, seeking a ruling that its broadcasts did not infringe their copyrights.

It said the U.S. Copyright Act allowed it to transmit copyrighted works from stations in New York, Los Angeles, Chicago and Seattle.

Viewers could access more than 20 channels for $4.99 per month, plus an additional 99 cents for the ability to pause, rewind and fast-forward.

But Buchwald said it is "extraordinarily unlikely" that ivi might ultimately qualify as a cable system entitling it to broadcast the shows.

A contrary result "essentially means that anyone with a computer, Internet connection, and TV antenna can become a 'cable system,'" Buchwald wrote. "It cannot be seriously argued that this is what Congress intended."

Ivi, she added, "cannot seriously argue that the existence of thousands of companies who legitimately use plaintiffs' programing and pay full freight means that ivi's illegal and uncompensated use does not irreparably harm plaintiffs."

The case is WPIX Inc et al v. Ivi Inc, U.S. District Court, Southern District of New York, No. 10-07415.

(Reporting by Jonathan Stempel in New York; additional reporting by Jennifer Saba, editing by Matthew Lewis)